👷 Migrate unit tests from Karma/Jasmine to Vitest

.gitignore

@@ -35,3 +35,4 @@ playwright-report/
 # Claude Code local files
 *.local.md
 .claude/settings.local.json
+**/__screenshots__/

.gitlab-ci.yml

@@ -223,6 +223,7 @@ unit:
       junit: test-report/unit/*.xml
   script:
     - yarn
+    - yarn playwright install chromium --with-deps
     - yarn test:unit
   after_script:
     - node ./scripts/test/export-test-result.ts unit
@@ -285,14 +286,18 @@ unit-bs:
   extends:
     - .base-configuration
     - .bs-allowed-branches
+    - .resource-allocation-4-cpus
   interruptible: true
   resource_group: browserstack
+  timeout: 35 minutes
   artifacts:
+    when: always
     reports:
       junit: test-report/unit-bs/*.xml
   script:
     - yarn
-    - node scripts/test/ci-bs.ts test:unit
+    - yarn playwright install --with-deps
+    - FORCE_COLOR=1 node scripts/test/ci-bs.ts test:unit
   after_script:
     - node ./scripts/test/export-test-result.ts unit-bs
 

AGENTS.md

@@ -22,10 +22,10 @@ yarn build:apps
 yarn test:unit
 
 # Run specific test file
-yarn test:unit --spec packages/core/src/path/to/feature.spec.ts
+yarn vitest run packages/core/src/path/to/feature.spec.ts
 
 # Run tests on a specific seed
-yarn test:unit --seed 123
+yarn vitest run --sequence.seed 123
 
 # setup E2E tests (installs Playwright and builds test apps)
 yarn test:e2e:init
@@ -66,7 +66,7 @@ test/
 ├── apps/            # Test apps for E2E and performance testing
 ├── e2e/             # Playwright E2E test scenarios
 ├── performance/     # Performance benchmarking tests
-└── unit/            # Karma/Jasmine unit test configuration
+└── unit/            # Vitest unit test configuration
 
 scripts/             # Build, deploy, release automation
 ```
@@ -86,9 +86,9 @@ For deeper context, see:
 
 ### Unit Tests
 
-- Test framework: Jasmine + Karma. Spec files co-located with implementation: `feature.ts` → `feature.spec.ts`
-- Focus tests with `fit()` / `fdescribe()`, skip with `xit()` / `xdescribe()`
+- Spec files co-located with implementation: `feature.ts` → `feature.spec.ts`
 - Use `registerCleanupTask()` for cleanup, NOT `afterEach()`
+- Test framework: Vitest (browser mode with Playwright)
 - Mock values/functions: wrap with `mockable()` in source, use `replaceMockable()` or `replaceMockableWithSpy()` in tests (auto-cleanup)
 
 ### Naming Conventions

LICENSE-3rdparty.csv

@@ -36,6 +36,9 @@ dev,@types/react-dom,MIT,Copyright Microsoft Corporation
 dev,@wxt-dev/module-react,MIT,Copyright (c) 2023 Aaron
 dev,@vitejs/plugin-react,MIT,Copyright (c) 2019-present Evan You & Vite Contributors
 dev,@vitejs/plugin-vue,MIT,Copyright (c) 2019-present, Yuxi (Evan) You and Vite contributors
+dev,@vitest/browser,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+dev,@vitest/browser-playwright,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
+dev,@vitest/coverage-istanbul,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
 dev,@module-federation/enhanced,MIT, Copyright (c) 2020 ScriptedAlchemy LLC (Zack Jackson) Zhou Shaw (zhouxiao)
 dev,@vue/test-utils,MIT,Copyright (c) 2021-present vuejs
 dev,ajv,MIT,Copyright 2015-2017 Evgeny Poberezkin
@@ -87,6 +90,7 @@ dev,typescript,Apache-2.0,Copyright Microsoft Corporation
 dev,typescript-eslint,MIT,Copyright (c) 2019 typescript-eslint and other contributors
 dev,undici,MIT,Copyright (c) Matteo Collina and Undici contributors
 dev,vite,MIT,Copyright (c) 2019-present, VoidZero Inc. and Vite contributors
+dev,vitest,MIT,Copyright (c) 2021-Present VoidZero Inc. and Vitest contributors
 dev,vue,MIT,Copyright (c) 2018-present, Yuxi (Evan) You
 dev,nuxt,MIT,Copyright (c) 2016-present Nuxt Team
 dev,vue-router,MIT,Copyright (c) 2019-present Eduardo San Martin Morote

developer-extension/package.json

@@ -11,7 +11,8 @@
     "@types/react": "19.2.14",
     "@types/react-dom": "19.2.3",
     "@wxt-dev/module-react": "1.2.2",
-    "typescript": "6.0.3"
+    "typescript": "6.0.3",
+    "vite": "8.0.8"
   },
   "dependencies": {
     "@datadog/browser-core": "workspace:*",

developer-extension/src/panel/components/tabs/eventsTab/computeFacetState.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { RumActionEvent, RumResourceEvent } from '@datadog/browser-rum'
 import { FacetRegistry } from '../../../hooks/useEvents'
 import type { FacetValuesFilter } from '../../../hooks/useEvents'

developer-extension/src/panel/components/tabs/eventsTab/copyEvent.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { TelemetryEvent } from '../../../../../../packages/core/src/domain/telemetry'
 import type { LogsEvent } from '../../../../../../packages/logs/src/logsEvent.types'
 import type { RumEvent } from '../../../../../../packages/rum-core/src/rumEvent.types'

developer-extension/src/panel/flushEvents.spec.ts

@@ -1,15 +1,16 @@
+import { vi, beforeEach, describe, expect, it, type Mock } from 'vitest'
 import type { Configuration } from '@datadog/browser-core'
 import { registerCleanupTask } from '../../../packages/core/test'
 import type { PageMayExitEvent } from '../../../packages/core/src/browser/pageMayExitObservable'
 import { createPageMayExitObservable } from '../../../packages/core/src/browser/pageMayExitObservable'
 import { flushScript } from './flushEvents'
 
 describe('flushEvents', () => {
-  let onExitSpy: jasmine.Spy<(event: PageMayExitEvent) => void>
+  let onExitSpy: Mock<(event: PageMayExitEvent) => void>
   let configuration: Configuration
 
   beforeEach(() => {
-    onExitSpy = jasmine.createSpy()
+    onExitSpy = vi.fn()
     configuration = {} as Configuration
     registerCleanupTask(createPageMayExitObservable(configuration).subscribe(onExitSpy).unsubscribe)
   })

developer-extension/src/panel/hooks/useEvents/eventFilters.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import type { RumEvent } from '../../../../../packages/rum-core/src/rumEvent.types'
 import type { LogsEvent } from '../../../../../packages/logs/src/logsEvent.types'
 import { isSafari } from '../../../../../packages/core/src/tools/utils/browserDetection'

developer-extension/src/panel/hooks/useEvents/facetRegistry.spec.ts

@@ -1,10 +1,12 @@
+import { beforeEach, describe, expect, it } from 'vitest'
 import { isChromium } from '../../../../../packages/core/src/tools/utils/browserDetection'
 import { getAllFields } from './facetRegistry'
 
 describe('getAllFields', () => {
-  beforeEach(() => {
+  beforeEach((ctx) => {
     if (!isChromium()) {
-      pending('Extension only supported in chromium')
+      ctx.skip()
+      return
     }
   })
 

eslint.config.mjs

@@ -469,17 +469,25 @@ export default tseslint.config(
   },
 
   {
-    files: ['**/webpack.*.{ts,mts}', 'eslint-local-rules/**/*.js'],
+    files: ['**/webpack.*.{ts,mts}', 'eslint-local-rules/**/*.js', 'vitest.config.ts', 'vitest.bs.config.ts'],
     rules: {
-      // Webpack configuration files and eslint rules files are expected to use a default export.
+      // Webpack configuration files, eslint rules files, and vitest config are expected to use a default export.
       'import/no-default-export': 'off',
     },
   },
 
   {
-    files: ['test/e2e/**/*.ts', 'test/performance/**/*.ts'],
+    files: [
+      'test/e2e/**/*.ts',
+      'test/performance/**/*.ts',
+      SPEC_FILES,
+      'packages/*/test/**/*.ts',
+      'test/unit/**/*.ts',
+      'vitest.config.ts',
+      'vitest.bs.config.ts',
+    ],
     rules: {
-      // E2E codebase is importing @datadog/browser-* packages referenced by tsconfig.
+      // E2E, test utilities, and spec files import packages referenced by tsconfig or root devDependencies (vitest).
       'import/no-extraneous-dependencies': 'off',
     },
   },

package.json

@@ -26,10 +26,10 @@
     "dev-server": "node scripts/dev-server/index.ts",
     "release": "node ./scripts/release/prepare-release.ts --push",
     "test": "yarn test:unit:watch",
-    "test:unit": "karma start ./test/unit/karma.local.conf.js",
+    "test:unit": "vitest run",
     "test:script": "node --test --experimental-test-module-mocks './scripts/**/*.spec.*'",
-    "test:unit:watch": "yarn test:unit --no-single-run",
-    "test:unit:bs": "node --env-file-if-exists=.env ./scripts/test/bs-wrapper.ts karma start test/unit/karma.bs.conf.js",
+    "test:unit:watch": "vitest",
+    "test:unit:bs": "node ./scripts/test/bs-wrapper.ts vitest run --config vitest.bs.config.ts",
     "test:e2e:init": "yarn build && yarn build:apps && yarn playwright install chromium --with-deps",
     "test:e2e": "playwright test --config test/e2e/playwright.local.config.ts --project chromium",
     "test:e2e:bs": "node --env-file-if-exists=.env ./scripts/test/bs-wrapper.ts playwright test --config test/e2e/playwright.bs.config.ts",
@@ -57,6 +57,9 @@
     "@types/jasmine": "3.10.19",
     "@types/node": "25.6.0",
     "@types/node-forge": "1.3.14",
+    "@vitest/browser": "4.0.18",
+    "@vitest/browser-playwright": "4.0.18",
+    "@vitest/coverage-istanbul": "4.0.18",
     "ajv": "8.20.0",
     "browserstack-local": "1.5.13",
     "busboy": "1.6.0",
@@ -97,6 +100,7 @@
     "typescript": "6.0.3",
     "typescript-eslint": "8.59.1",
     "undici": "8.1.0",
+    "vitest": "4.0.18",
     "webpack": "5.106.2",
     "webpack-cli": "7.0.2",
     "webpack-dev-middleware": "8.0.3"

packages/core/src/boot/displayAlreadyInitializedError.spec.ts

@@ -1,17 +1,18 @@
+import { vi, describe, expect, it } from 'vitest'
 import type { InitConfiguration } from '../domain/configuration'
 import { display } from '../tools/display'
 import { displayAlreadyInitializedError } from './displayAlreadyInitializedError'
 
 describe('displayAlreadyInitializedError', () => {
   it('should display an error', () => {
-    const displayErrorSpy = spyOn(display, 'error')
+    const displayErrorSpy = vi.spyOn(display, 'error')
     displayAlreadyInitializedError('DD_RUM', {} as InitConfiguration)
     expect(displayErrorSpy).toHaveBeenCalledTimes(1)
     expect(displayErrorSpy).toHaveBeenCalledWith('DD_RUM is already initialized.')
   })
 
   it('should not display an error if the "silentMultipleInit" option is used', () => {
-    const displayErrorSpy = spyOn(display, 'error')
+    const displayErrorSpy = vi.spyOn(display, 'error')
     displayAlreadyInitializedError('DD_RUM', { silentMultipleInit: true } as InitConfiguration)
     expect(displayErrorSpy).not.toHaveBeenCalled()
   })

packages/core/src/boot/init.spec.ts

@@ -1,3 +1,4 @@
+import { vi, describe, expect, it } from 'vitest'
 import { display } from '../tools/display'
 import { defineGlobal } from './init'
 
@@ -17,8 +18,8 @@ describe('defineGlobal', () => {
   })
 
   it('run the queued callbacks on the old value', () => {
-    const fn1 = jasmine.createSpy()
-    const fn2 = jasmine.createSpy()
+    const fn1 = vi.fn()
+    const fn2 = vi.fn()
     const myGlobal: any = {
       foo: {
         q: [fn1, fn2],
@@ -42,7 +43,7 @@ describe('defineGlobal', () => {
         q: [onReady],
       },
     }
-    const displaySpy = spyOn(display, 'error')
+    const displaySpy = vi.spyOn(display, 'error')
 
     defineGlobal(myGlobal, 'foo', {})
     expect(displaySpy).toHaveBeenCalledWith('onReady callback threw an error:', myError)

packages/core/src/browser/addEventListener.spec.ts

@@ -1,3 +1,4 @@
+import { vi, beforeEach, describe, expect, it } from 'vitest'
 import type { Configuration } from '../domain/configuration'
 import { createNewEvent, mockZoneJs, registerCleanupTask } from '../../test'
 import type { MockZoneJs } from '../../test'
@@ -16,7 +17,7 @@ describe('addEventListener', () => {
     })
 
     it('uses the original addEventListener method instead of the method patched by Zone.js', () => {
-      const zoneJsPatchedAddEventListener = jasmine.createSpy()
+      const zoneJsPatchedAddEventListener = vi.fn()
       const eventTarget = document.createElement('div')
       zoneJs.replaceProperty(eventTarget, 'addEventListener', zoneJsPatchedAddEventListener)
 
@@ -25,7 +26,7 @@ describe('addEventListener', () => {
     })
 
     it('uses the original removeEventListener method instead of the method patched by Zone.js', () => {
-      const zoneJsPatchedRemoveEventListener = jasmine.createSpy()
+      const zoneJsPatchedRemoveEventListener = vi.fn()
       const eventTarget = document.createElement('div')
       zoneJs.replaceProperty(eventTarget, 'removeEventListener', zoneJsPatchedRemoveEventListener)
 
@@ -41,17 +42,17 @@ describe('addEventListener', () => {
     // eslint-disable-next-line @typescript-eslint/unbound-method
     const originalRemoveEventListener = EventTarget.prototype.removeEventListener
 
-    EventTarget.prototype.addEventListener = jasmine.createSpy()
-    EventTarget.prototype.removeEventListener = jasmine.createSpy()
+    EventTarget.prototype.addEventListener = vi.fn()
+    EventTarget.prototype.removeEventListener = vi.fn()
 
     registerCleanupTask(() => {
       EventTarget.prototype.addEventListener = originalAddEventListener
       EventTarget.prototype.removeEventListener = originalRemoveEventListener
     })
 
     const htmlDivElement = document.createElement('div')
-    htmlDivElement.addEventListener = jasmine.createSpy()
-    htmlDivElement.removeEventListener = jasmine.createSpy()
+    htmlDivElement.addEventListener = vi.fn()
+    htmlDivElement.removeEventListener = vi.fn()
 
     const { stop } = addEventListener({ allowUntrustedEvents: false }, htmlDivElement, DOM_EVENT.CLICK, noop)
 
@@ -71,11 +72,11 @@ describe('addEventListener', () => {
   })
 
   it('Use the addEventListener method when the eventTarget is not an instance of EventTarget', () => {
-    const listener = jasmine.createSpy()
+    const listener = vi.fn()
 
     const customEventTarget = {
-      addEventListener: jasmine.createSpy(),
-      removeEventListener: jasmine.createSpy(),
+      addEventListener: vi.fn(),
+      removeEventListener: vi.fn(),
     } as unknown as HTMLElement
 
     const { stop } = addEventListener({ allowUntrustedEvents: false }, customEventTarget, 'change', listener)
@@ -93,7 +94,7 @@ describe('addEventListener', () => {
     })
 
     it('should be ignored if __ddIsTrusted is absent', () => {
-      const listener = jasmine.createSpy()
+      const listener = vi.fn()
       const eventTarget = document.createElement('div')
       addEventListener(configuration, eventTarget, DOM_EVENT.CLICK, listener)
 
@@ -103,7 +104,7 @@ describe('addEventListener', () => {
     })
 
     it('should be ignored if __ddIsTrusted is false', () => {
-      const listener = jasmine.createSpy()
+      const listener = vi.fn()
       const eventTarget = document.createElement('div')
       addEventListener(configuration, eventTarget, DOM_EVENT.CLICK, listener)
 
@@ -113,7 +114,7 @@ describe('addEventListener', () => {
     })
 
     it('should not be ignored if __ddIsTrusted is true', () => {
-      const listener = jasmine.createSpy()
+      const listener = vi.fn()
       const eventTarget = document.createElement('div')
       addEventListener(configuration, eventTarget, DOM_EVENT.CLICK, listener)
 
@@ -124,7 +125,7 @@ describe('addEventListener', () => {
     })
 
     it('should not be ignored if allowUntrustedEvents is true', () => {
-      const listener = jasmine.createSpy()
+      const listener = vi.fn()
       const eventTarget = document.createElement('div')
       configuration = { allowUntrustedEvents: true } as Configuration
 

packages/core/src/browser/cookie.spec.ts

@@ -1,3 +1,4 @@
+import { describe, expect, it } from 'vitest'
 import { mockCookies } from '../../test'
 import { getCurrentSite } from './cookie'
 

packages/core/src/browser/fetch.spec.ts

@@ -1,3 +1,4 @@
+import { vi, beforeEach, describe, expect, it } from 'vitest'
 import { type MockZoneJs, mockZoneJs } from '../../test'
 import { fetch } from './fetch'
 
@@ -9,8 +10,8 @@ describe('fetch', () => {
   })
 
   it('does not use the Zone.js function', async () => {
-    const nativeFetchSpy = spyOn(window, 'fetch')
-    const zoneJsFetchSpy = jasmine.createSpy('zoneJsFetch')
+    const nativeFetchSpy = vi.spyOn(window, 'fetch').mockResolvedValue(new Response())
+    const zoneJsFetchSpy = vi.fn()
 
     zoneJs.replaceProperty(window, 'fetch', zoneJsFetchSpy)
 
@@ -21,8 +22,8 @@ describe('fetch', () => {
   })
 
   it('calls the native fetch function with correct arguments', async () => {
-    const nativeFetchSpy = spyOn(window, 'fetch')
-    const zoneJsFetchSpy = jasmine.createSpy('zoneJsFetch')
+    const nativeFetchSpy = vi.spyOn(window, 'fetch').mockResolvedValue(new Response())
+    const zoneJsFetchSpy = vi.fn()
 
     zoneJs.replaceProperty(window, 'fetch', zoneJsFetchSpy)
 
@@ -33,8 +34,8 @@ describe('fetch', () => {
 
   it('returns the response from native fetch', async () => {
     const mockResponse = new Response('test response', { status: 200 })
-    spyOn(window, 'fetch').and.returnValue(Promise.resolve(mockResponse))
-    const zoneJsFetchSpy = jasmine.createSpy('zoneJsFetch').and.returnValue(Promise.resolve(new Response()))
+    vi.spyOn(window, 'fetch').mockReturnValue(Promise.resolve(mockResponse))
+    const zoneJsFetchSpy = vi.fn().mockReturnValue(Promise.resolve(new Response()))
 
     zoneJs.replaceProperty(window, 'fetch', zoneJsFetchSpy)